Prior to advent of Sapphire Expression Language, sdef language included the "use-model-element-image" switch
as a way to indicate to the system that content outline node's image should be the same as the image for the
associated model element. With advent of EL, the special switch is no longer necessary as an expression can be used
to capture the same semantics.

The Graphiti-based diagram presentation (introduced in 0.4 release) has been replaced with a presentation
written directly on top of GEF. This has significantly reduced Sapphire's dependencies and enabled diagram
support to more tightly integrate with the rest of Sapphire.